1、Designation: D5178 16Standard Test Method forMar Resistance of Organic Coatings1This standard is issued under the fixed designation D5178; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A number in paren
2、theses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers the determination of the marresistance on smooth, flat surfaces. Results are expressed interms of force-to-mar films of organi
3、c coatings such as paint,varnish, and lacquer when applied to smooth, flat planar panelsurfaces.1.2 The values stated in inch-pound units are to be regardedas standard. The values given in parentheses are mathematicalconversions to SI units that are provided for information onlyand are not considere
4、d standard.1.3 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. R
5、eferenced Documents2.1 ASTM Standards:2D609 Practice for Preparation of Cold-Rolled Steel Panelsfor Testing Paint, Varnish, Conversion Coatings, andRelated Coating ProductsD823 Practices for Producing Films of Uniform Thicknessof Paint, Varnish, and Related Products on Test PanelsD1005 Test Method f
6、or Measurement of Dry-Film Thick-ness of Organic Coatings Using MicrometersD1186 Test Methods for Nondestructive Measurement ofDry Film Thickness of Nonmagnetic Coatings Applied toa Ferrous Base (Withdrawn 2006)3D1400 Test Method for Nondestructive Measurement of DryFilm Thickness of Nonconductive C
7、oatings Applied to aNonferrous Metal Base (Withdrawn 2006)3D2691 Method for Microscopical Measurement of Dry FilmThickness of Coatings on Wood Products (Withdrawn1992)3E177 Practice for Use of the Terms Precision and Bias inASTM Test MethodsE691 Practice for Conducting an Interlaboratory Study toDet
8、ermine the Precision of a Test Method3. Terminology3.1 Definitions:3.1.1 mar resistance, nthe ability of a coating to resistdamage caused by light abrasion. As just defined, it is aresistance of the surface of the coating to permanentdeformation, resulting from the application of a dynamicmechanical
9、 force.4. Summary of Test Method4.1 The materials under test are applied at uniform thicknessto flat panels of uniform surface texture. After drying/curing,the mar resistance is determined by pushing the panels beneatha rounded stylus or loop that is loaded in increasing amountsuntil the coating is
10、marred.5. Significance and Use5.1 In some situations, marring of coatings applied tosubstrates under typical use conditions is unacceptable. Thistest method has been found useful in differentiating the degreeof marring of coatings on substrates. It is most useful inproviding relative ratings for a s
11、eries of coated panels exhib-iting significant differences in marring.5.2 In a limited laboratory study, meaningful mar resultswere impossible when powder coatings were tested. The marmarking, that is, scratches, became less perceptible with time.Therefore, powder coatings may not be applicable coat
12、ings forthis test method.6. Apparatus6.1 Application Equipment, as described in Practices D823.6.2 Film-Thickness Measuring Apparatus, as described inTest Methods D1005, D1186, D1400,orD2691.6.3 Balanced Beam Scrape Adhesion and Mar Tester (Fig. 1and Fig. 2), consisting of a balanced beam to which i
13、s secureda platform for supporting weights, and a rod at an angle of 451This test method is under the jurisdiction of ASTM Committee D01 on Paintand Related Coatings, Materials, and Applications and is the direct responsibility ofSubcommittee D01.23 on Physical Properties of Applied Paint Films.Curr
14、ent edition approved Dec. 1, 2016. Published January 2017. Originallyapproved in 1991. Last previous edition approved in 2013 as D5178 13. DOI:10.1520/D5178-16.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of
15、 ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3The last approved version of this historical standard is referenced onwww.astm.org.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United StatesThis
16、 international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TB
17、T) Committee.1that holds the scraping loop. The rod shall be set so that thescraping loop contacts test surfaces directly below the weights.The loop shall be116-in. (1.6 mm) diameter rod, bent into a“U” shape with an outside radius of 0.128 6 0.002 in. (3.25 60.05 mm) and hardened to Rockwell HRC 56
18、 to 58, and shallbe a smooth finish. The loop can be either chromium plated,nickel plated, or heat treated polished steel as agreed uponbetween the purchaser and the supplier. These testers areadjustable to accommodate flat, metallic, and nonmetallicspecimens to 0.5-in. (12-mm) thick and 4 to 16 in.
19、 (100 to 400mm) wide and long; the specimen should be at least12-in.(12-mm) wide.7. Preparation of Specimens7.1 Apply the materials under test to panels of the compo-sition and surface condition on which it is desired to determinemar resistance of the coating. The panel material (7.1.1),surface prep
20、aration, thickness, and number of coats shall bespecified or agreed upon between the seller and the purchaser.Apply coatings and air dry or bake under conditions ofhumidity and temperature mutually agreeable to the seller andthe purchaser.7.1.1 The surface of the coating must be hard enough toresist
21、 damage by the scraping loop at a load agreed uponbetween the producer and the user. If no panel material isspecified, use 0.032-in. (0.8-mm) cold-rolled carbon steelprepared in accordance with Methods B or C of Practice D609.8. Conditioning and Number of Tests8.1 Condition the test panels for at le
22、ast 48 h at 23 6 2C(73.5 6 3.5F) and 50 6 5 % relative humidity, and test in thesame environment, or immediately on removal therefrom,unless otherwise specified or agreed upon by the seller and thepurchaser. Test at least two replicate specimens of eachmaterial.9. Procedure9.1 In preparation for usi
23、ng the apparatus, ensure that it isreasonably level and place it so that the weight holder is towardthe operator. This places the beam release on the operatorsright and allows freedom to move the test specimen manuallyunder the weighted scraping element (loop). Insert the loopinto the holder as far
24、as it will go and tighten the clampingscrew. Adjust the main bearing support so that the beam isFIG. 1 Balanced Beam Scrape Adhesion and Mar TesterFIG. 2 Balanced Beam Scrape Adhesion and Mar TesterD5178 162balanced in the horizontal plane when the loop is just touchingthe specimen surface. The alig
25、nment of the beam should besuch that the end of the loop is over the midline of the movabletable.9.2 Raise the beam and lock it in the raised position. Wipethe loop with a clean cloth or chamois. Locate the specimen onthe sliding platform against the stop so that the specimen canbe moved away from t
26、he operator and there is an area at least3 in. (75 mm) long by12 in. (12 mm) wide on the sampleparallel to the horizontal plane through the beam. Placeweights on the weight support using an initial amount that isestimated to be appropriate for the particular coating. Releasethe beam and carefully lo
27、wer it until the loop rests on thecoated test specimen and the full load is applied, then slowlypush the sliding platform away from the operator at a rate of14in. (6 mm)/s for a distance of at least 3 in. (75 mm). If thecoating is marred, continue the testing using successivelysmaller loads (0.5-kg
28、increments) until the coating is notmarred. If the coating is not marred by the initial scrape,continue the test using successively larger loads (0.5-kgincrements) until the coating is marred or until the maximumload of 10 kg has been applied. Use a new area of the testsurface each time a scrape is
29、made.9.3 When the critical load has been approximately located,repeat the test five times at each of three loadings: above,below and at the load determined in the first trial. Use thereplicate specimen to apply different loads in random fashionso the same load is not made in succession.9.3.1 Periodi
30、cally examine the loop to ensure that theoriginal smooth surface is intact. If the contacting surface isworn, reverse the loop. When both sides are worn, replace witha new loop.9.4 For each applied load, tabulate the number of times thecoating was marred.10. Report10.1 Report the following informati
31、on:10.1.1 Load in kilograms at the mar failure end point,10.1.2 Panel material and surface preparation,10.1.3 “U” shape loop surface finish,10.1.4 Dry-film thickness, and10.1.5 Any deviation from the specified procedure.11. Precision and Bias11.1 The precision of this test method is based on aninter
32、laboratory study of D5178, Standard Test Method for MarResistance of Organic Coatings, conducted in 2015. Sixlaboratories tested three panel pairings. Every “test result”represents an individual determination. Practice E691 wasfollowed for the design and analysis of the data; the details aregiven in
33、 ASTM Research Report No: RR:D01-1182.411.1.1 Repeatability (r)The difference between repetitiveresults obtained by the same operator in a given laboratoryapplying the same test method with the same apparatus underconstant operating conditions on identical test material withinshort intervals of time
34、 would in the long run, in the normal andcorrect operation of the test method, exceed the followingvalues only in one case in 20.11.1.1.1 Repeatability can be interpreted as maximum dif-ference between two results, obtained under repeatabilityconditions that are accepted as plausible due to random c
35、ausesunder normal and correct operation of the test method.11.1.1.2 Repeatability limits are listed in Table 1 and Table2.11.1.2 Reproducibility (R)The difference between twosingle and independent results obtained by different operators4Supporting data have been filed at ASTM International Headquart
36、ers and maybe obtained by requesting Research Report RR:D01-1182. ContactASTM CustomerService at serviceastm.org.TABLE 1 Film Thickness (microns)MaterialAverageAXRepeatabilityStandardDeviationsrReproducibilityStandardDeviationSRRepeatabilityLimitrReproducibilityLimitRPanel Set E and RB109.9 32.2 37.
37、5 90.2 105.0Panel Set B and HB93.3 10.9 10.9 30.4 30.6Panel Set D and GB74.0 25.2 25.2 70.4 70.4AThe average of the laboratories averages.BFive laboratories reported results.TABLE 2 Load at the Mar Failure End Point (kg)MaterialAverageAXRepeatabilityStandardDeviationsrReproducibilityStandardDeviatio
38、nSRRepeatabilityLimitrReproducibilityLimitRPanel Set E and RB7.05 0.88 1.98 2.46 5.55Panel Set B and HB1.52 1.34 1.34 3.75 3.75Panel Set D and G 1.25 0.93 0.93 2.60 2.60AThe average of the laboratories averages.BFive laboratories reported results.D5178 163applying the same test method in different l
39、aboratories usingdifferent apparatus on identical test material would, in the longrun, in the normal and correct operation of the test method,exceed the following values only in one case in 20.11.1.2.1 Reproducibility can be interpreted as maximumdifference between two results, obtained under reprod
40、ucibilityconditions that are accepted as plausible due to random causesunder normal and correct operation of the test method.11.1.2.2 Reproducibility limits are listed in Table 1 andTable 2.11.1.3 The above terms (repeatability limit and reproduc-ibility limit) are used as specified in Practice E177
41、.11.1.4 Any judgment in accordance with statements 11.1.1and 11.1.2 would have an approximate 95 % probability ofbeing correct.11.2 BiasAt the time of the study, there was no acceptedreference material suitable for determining the bias for this testmethod, therefore no statement on bias is being mad
42、e.11.3 The precision statement was determined through sta-tistical examination of 62 test results, from a total of 6laboratories, on 3 pairings of materials. The materials usedwere described as the following:Panel set B: Polyurethane CoatingPanel set D: Epoxy CoatingPanel set E: Polysiloxane Coating
43、Panel set G: Epoxy CoatingPanel set H: Polyurethane CoatingPanel set R: Polysiloxane Coating11.4 To judge the equivalency of two test results, it isrecommended to choose the panel set type closest in charac-teristics to the test panels.12. Keywords12.1 balanced beam scrape adhesion and mar tester; b
44、al-anced beam tester; coatings; mar or organic mar resistanceASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such p
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48、ndard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org). Permission rights to photocopy the standard may also be secured from the Copyright Clearance Center, 222Rosewood Drive, Danvers, MA 01923, Tel: (978) 646-2600; http:/ 164
